We are proposing to continue structural analysis of eggshell (chorion) proteins of silkmoths to determine the nature of the multigene family which encodes them. Additional protein and nucleic acid sequencing should reveal new pathways of evolutionary diversification and clarify the relationships among the multiplicity of chorion proteins. Combined with our knowledge of the developmental program of protein synthesis and our studies in progress on the nature of chorion gene organization within the chromosome using chromosomal fragments inserted, cloned and amplified in plasmids, we should be able to interpret evolutionary change, developmental regulation and gene organization in terms of each other. We also propose to continue a structure-function analysis of several proteins which have been localized to specific chorion substructures. Protein sequencing will be used to identify structural domains potentially important for formation of the observed ultrastructure. More detailed localization using chorion-specific antibodies will enable us to study localization as a cellular process.